Electric heating.



No. '75?,633. PATBNTED APB. 19, 1904. E, E. PM IE.

ELETRIG HEATING.

APPLIUATION FILED APB. 5. 1902.

No MODEL.

nf m? MW harz, 9 lv "To @ZZ whom it may concern'.-

" UARBIDE COMPANY, FALLS,2NEW YORK, A -COROR'ATGN v IRG-INIA. i

" 'negeert-uo Hearings..

"SPECIFICATION aanleg'- 'part of Letters Patent are. 757,633, dates .apra ie, ieee.

' appunti@ had Aprile, 1902. steun. 101,502. en man.)

Beit known that I, EDGAR F.'PICE, a citi- ;zen of the United States, residing" at Niagara' Falls, in the county of. Niagara and State lof New York, have invented certain new and use- I ful Improvements in ElectricxHeating, of which the following` is a specihcation. '1

This,y invention relates to the art of electricy ally heating materials, especially mixtures of ametallic compound and a reducing agent',-

Vand specifically a mixture of lime and carbon for the production of calcium carbid. The

processicontemplates the use as a heating means of a resistance-conductor placed in proximity to the materials to be heated. .This conductor is heated by superposed electric currents passed through it, and the density of the current is thus increased along its path, thereby heating the conductor non-uniformly.

The process may be carriedout by different forms of apparatus, two of which are shown in the accompanying drawin ,rs, in whichyFigure 1 isa vertical axial section of a stackfurnace, and Fig. 2 is a Vertical longitudinal section of a horizontal or reverberatory fur- The furnace shown in lFig. l lcomprises a vertical stack l and frustb-conicalbosh 2, of suitable refractory non-ccnductin'g material, such as fire-brick, and a cijucible or hearth 8, of refractory conducting material, such as carbon. rlhe hearth is provided with a tap-. hole 4. A series of 'electrndes 5, arranged in a ring, dependl into the 'upper part of 'the stack. One or morehorizdntal series of radial leloctrodes 6 7 Vmay extend through the sides of the stack and bosh. The electrodes 5 6 7,

' which may be carbon rods, are` connected to one 'terminal of a source of electric current, such as -a direct-current or alternating-current dynamo, and the hearth 3 is connected .to the other terminal. Withinthe furnace and in `contact with its walls is a tubular resistancef conductor 8, preferably of lose material, such as lumps of graphitized carbon or` coke. The charge of n'iaterialtov be heated,`9, is ar-V l ranged as 'a vertical column withinand in contac. with the.,resistance-conductor; It' will be' seen that the`,resistancc-conductor 8 by reason of the conical 1nosh 2 decreases in Temse-sectional area Itrrward the hearth, and its resistance thereby increases downwardly. When' an yelectric current is passe-d between one of the vupper `electrodes and the hearth, the resistancefconductor 1s non-uniformly heated.y byl reason 'i of the gradually-increasing current density toward the hearth. 'llheheat i generated bythe passage of the currengp and radiated to thematerial 9 thus increasesl o. wir

wardly. rThel :current density in the lewer part of the resistance-conductor is `further increased. by supplying additional current through the radial electrodes t3 and 7 the cur rent flowing between the'electrcdes 6 and the hearth being superpcsed upon that passing between the upper electrodes 5 and the hearth and the current traversinpg'the lower part of the re sista'nce-conductor being supplemented by the amounts supplied by the lower electrodes 7.,

As the lower part of the celu 'c1119 of material to be heated-for example, a mixture of lime and carbon-1s brought to a sucient temperature the materials react to form calcium carbid, i lwhich may be allowed to accumulate as a pool in hearth 3 and drawn off from time 'to time through tap-hole fic or aliowed to run out continuously as produced. The column 9 thereupcn gradually descends, and fresh material is'fed in at the upper end. Such por tions of the resistance-conductor as are car ried down with the charge may also be replen ished at the upper part of the'furnace. The central column of material is heated not only by radiation and conduction fromthe sur` rounding resistance-conductor, but also by the waste gases passing up from'the zones of reduction and fusion below. The resistanceconductor surrounding the column of materialto be heated efficiently prevents loss of heat therefrom by radiation.

e The furnace shown in ldig. 2 comprises end walls l0 l1, floor-l2, and roof 13, of refractory non-conducting material, lsuch as lire brick.: A feed-hopper la' and Waste-gas pipe 21 pass through thereof. @n the floor ofthe furnace lies a reslstanceeonductor1.9, preferrennes the resistanceof the conductor causes the materials t react to form carbid, and the carbid to be brought into a molten cordition, as set forth.

9. The process of producing carbids, Which consists 1n placing carbid-forming materials m proximity to a stable resistance-conductor,

passing superposed electric currents through said conductor, thereby increasing the current density along the path of the current through a portion of the conductor in proximity to said material to a point Where the heat. generated by theresistance of the conductor causes the materials to react to form carbid, and the carbid to be brought into a molten condition, and tapping off said molten carbid and supplying fresh material as required, as set forth.

10. The process of producing cai-bids, which consists in placing carbid-forming materials in proximity to a resistance-conductor of loose, broken or granular material, passing superposed electric currents through said conductor, thereby increasing the current density along the path of the current through a portion of the conductor in proximity to said material to a point where the heat generated by the resistance of the conductor causes the materials to react to form carbid, and the carbid to be brought into a molten condition, and tapping off said molten carbid and supplying fresh material as required, as set forth.

11. The process of heating materials, which consists in placing the material in proximity to a stable resistance-conductor, and passing superposed electric currents through said conductor, thereby increasing the current density in a portion of said conductor in proximity to said material and heating it ununiformlyas set forth.

12. rEhe process of heating materials, which consists in placing the material in proximity to a resistance-conductor, of loose, broken or granular material, and passing superposed electric currents through said conductor, thereby increasing the current density in 'a portion of said conductor in proximity to said material and heating it ununiformly, as set forth.

13. The process of reducinga compound, whichconsists in. placing amixture of the compound and a reducing agent in proximity to a stable resistance-conductor, and passing superposed electric currents through said conductor, thereby increasing the current density in a portion of said lconductor in proximity to said material to a point Where the heat generated by the resistance of the conductor ejects reduction, as set forth.

14. The process 'f reducing a compound, which consists in placing a rmixture of the compound and areducing agent in proximity to a resistance-conductor, of loose, broiren or granular material, and passing super-posed electric currents through said conductor,

thereby increasing the current ldensity in a portion of said conductor in proximity to said material 'to a point Where the heat generated by the resistance-of the conductor effects reduction, as set forth.

15. rlhe process of producing cai-bids,which consists in placing carbid-forming materials in proximity to a stable resistance-conductor, and passing superposed electric currents through said conductor, thereby increasing the current density in a portion of said conductor in proximity to said material to a point where the heat generated by the resistance of the conductor causes the materials to react to A form carbid, as set forth.

16. The process of producing carbidawhich consists in placing carbid-forming materials in proximity to ya 'resistance-conductor,' of loose, broken or granular material, and passing superposed electric currents through said conductor, thereby increasing the current density in a portion of said conductor in proximity to said materialto a point Where the' heat-generated by the resistance of the conductor causes the materials to react to form carbid, as setforth. i

17,. The process of producing carbidawhich consists 1n placing carbid-forming materials in proximity to a stable resistancec0nductor,

passing superposed electric currents through said conductor, thereby increasing the cur rent density in a portion of said conductor in proximity to said material to a point vWhere the heat generated by the resistance of the conductor causes the materials to react to form carbid, and the carbid to be brought into a molten condition, and tappingo said molten carbid and supplyingfresh material, as ren quired, asset forthrf Y, 'c f 18. The process of producing carbids,which consists -in lacin@r carbid-funding materiais in proximity to a resistance -vconductoig of loose, broken or granular materiahpassing superposed electric currents through said conductor, thereby increasing the current density in a portion of said conductor in proximityto said material to apoint Where the heat generatedt by the resistance of A the conductor causes the materials to react to form carbid', and the carbid to be brought `into a molten condition, and tapping off said molten carbid and supplying fresh material as required., as set forth.

EDGAR F.. T?RE.

Witnesses:

A.. B. Strououroln, K. M. Gamesa,

IOO 

